JP2001005424A - Plasma display panel and its drive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive method displaying a high quality image without a flicker, a luminance shortage and a drop of contrast and displaying a high gradation display without a long scanning period for a write-in discharge even when the number of scan electrodes are increased in an AC discharge type PDP(plasma display panel). SOLUTION: This drive method reduces dispersion in a delay time of a discharge even in the hourly later write-in discharge and eliminate the necessity of widening the width of a data pulse by gradually increasing the amplitude of the data pulses vd1,...., vdn in accordance with the lapse of time from a scan start when the data pulses vd1,...., vdn synchronized with a scanning pulse are applied selectively to a data electrode of a discharge cell to be displayed among the discharge cells on the scan electrodes applied with the scan pulse and the write-in discharge is caused in the discharge cell to be discharged while line sequentially applying the scan pulses vs1,...., vsn to the scan electrodes in the scanning period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP) and a method of driving the same, and more particularly, to an AC discharge type PDP for displaying a scan electrode by applying a scan pulse to a scan electrode in a line-sequential manner and a method of driving the PDP.

[0002]

2. Description of the Related Art A PDP of this type basically has a plurality of pairs of scan electrodes and common electrodes running in parallel with each other, a plurality of data electrodes extending in a direction perpendicular to the scan electrodes and the common electrodes, and a plurality of scan electrodes. And a discharge cell arranged at a matrix intersection where the pair of common electrodes and the data electrode intersect. When driving the panel, a pulse (scanning pulse) is applied to the scanning electrode in a line-sequential manner. While selectively applying a pulse (data pulse) to the data electrode while selecting a cell to be displayed (discharge emission),
Desired image display is performed by gradation control based on the subfield method. Hereinafter, selection of display cells by line-sequential driving and gradation control by the subfield method will be described.

FIG. 6A schematically shows a general planar structure of an AC discharge type PDP. Referring to FIG.
In the PDP shown in this figure, n parallel scanning electrodes S1,
{N common electrodes C1}, C similar to Sn
n run in the left-right direction on the paper as a pair one by one. In the vertical direction of the paper, m data electrodes D1,.
Dm are laid in parallel. One discharge cell 10 is formed at each of the n × m intersections between the scan electrode, the common electrode, and the data electrode. FIG.
(A) is schematically shown by a solid circle.

FIG. 6B shows an example of a cross section of one discharge cell taken along the line Yy in FIG. 6A. FIG. 6 (b)
Referring to, the discharge cells divide the space between the front substrate 1A and the rear substrate 1B, which are arranged facing each other with a distance, from the partitions 4A1, 4B1, 4A provided on the substrates 1A, 1B.
It has a structure partitioned by 2,4B2. The partition partitions cells from each other so as not to be affected by discharge of an adjacent cell. The front substrate 1A is transparent and insulative, and a transparent scanning electrode S and a transparent common electrode C are formed in parallel with each other. The scanning electrode S and the common electrode C are both covered with a transparent dielectric layer 2 and a protective layer 3. The dielectric layer 2 is made of, for example, an insulating glaze layer, and the protective layer 3 is made of, for example, MgO.
Consists of Partition walls 4A1 and 4A2 are provided on the protective layer 3 at positions sandwiching the scanning electrode and the common electrode. The back substrate 1B is also transparent and insulative, and data electrodes D are formed on the substrate in a direction orthogonal to the scanning electrodes S and the common electrodes C. The data electrode D is covered with a dielectric layer 5 made of a white insulating glaze layer. On the dielectric layer 5, the partition 4 is located at a position corresponding to the partitions 4A1 and 4A2 on the front substrate side.
B1 and 4B2 are set up. On the dielectric layer 5,
Further, RGB phosphors 6 are formed. Partition walls 4A1, 4
A rare gas such as He, Ne, Xe or the like is sealed in a certain ratio in the discharge gas space 8 partitioned by A2, 4B1, and 4B2, and is interposed between the scan electrode S, the common electrode C, and the data electrode D. When a voltage is applied to generate a discharge in this space 8,
The phosphors 6 are excited by ultraviolet rays emitted from these gases, and emit light.

In order to cause the discharge cell shown in FIG. 6B to emit light, first, a voltage is applied between the scan electrode S and the data electrode D to cause a discharge in the discharge gas space 8 (address discharge). By the address discharge generated between the scan electrode S and the data electrode D, electrons and ions are generated in the gas space 8, and they are attracted by the electrodes having the opposite polarities to the respective charges, and Attach to insulating layer (wall charge).
The electric field generated by the wall charges has a polarity opposite to that of the electric field due to the voltage applied between the scan electrode S and the data electrode D. Therefore, the effective electric field between the scan electrode S and the data electrode D is reduced, and the discharge is performed. Stop once. Next, a voltage lower than the previous address discharge is applied between the scan electrode S and the common electrode C. At this time, a voltage having the same polarity as the wall charge attached to the electrode in the previous address discharge is applied between the scan electrode S and the common electrode C. As a result, the voltage of the wall charge attached in the previous address discharge is superimposed on the voltage applied later between the scan electrode S and the common electrode C, and the sum of these voltages makes the discharge threshold voltage. If it is set so as to exceed, the discharge once stopped discharges again at a lower voltage than the address discharge (sustain discharge). When stopping the sustain discharge, a low voltage or a short-time erasing voltage is applied between the scan electrode S and the common electrode C such that wall charges generated by the sustain discharge are neutralized.

A method of driving the PDP shown in FIG. 6A in a line-sequential manner will be described below based on the above-described method of emitting light in a single cell. FIG. 7 shows an example of a timing chart when the panel is driven line-sequentially. Referring to FIG. 7, this PDP basically includes a scanning period TS for selectively generating an address discharge only in a cell in which discharge light emission is desired.
And an erasing period TE for stopping the sustain discharge, and an erasing period TE for stopping the discharge of the cell in which the address discharge has occurred, an image for one field is displayed. Before the period TS, a priming period TP for generating a preliminary discharge (priming discharge) for easily causing an address discharge is often provided. In the following, a description will be given based on a driving method having a priming period according to many examples.

During the priming period TP, a priming pulse vp is applied to the scan electrodes and the common electrodes of all the cells to generate a priming discharge. As a result, charged particles and excited particles are generated to activate the inside of the cell, so that an address discharge is easily generated in the subsequent scanning period TS.

[0008] The scanning period TS is a period during which the address discharge is selectively generated only in the cells to be luminously displayed among all the cells in the panel. The sustain discharge is performed only in the cells to be luminously displayed in the next sustain period TC. This is the preparation period for making it work. During this scanning period, first, the first scanning electrode S
1. Next, the scan pulses vs1, vs2,..., Vsn are applied to each scan electrode in a line-sequential manner, such as the second scan electrode S2 and finally the n-th scan electrode Sn.
At this time, in synchronization with each scan pulse, a data pulse is applied to the data electrode of the cell to be made to emit light among the cells on the scan electrode to which the scan pulse is applied. No data pulse is applied to the data electrodes of the cells not to emit light. During this scanning period, the data pulse is v
As in the case of d1, vd2,..., vdn, the same number of times as the number of scanning electrodes occurs repeatedly. In FIG. 7, among the m cells on one scanning electrode, a cell to be displayed and a cell not to be displayed are mixed, that is, a cell to which a data pulse is applied to a data electrode and a cell to which a data pulse is not applied. That the data pulses vd1, vd
The pulse waveforms of 2, ‥‥, and vdn are indicated by hatching.

The data pulses vd1, vd2,..., Vd
n is generated by the data pulse generator 12 in the circuit block shown in FIG. The output timing and pulse width of each data pulse are controlled by a signal SG1 sent from the video signal processing unit 11 to the data pulse generation unit 12. FIG. 8 shows a circuit diagram of an example of the data pulse generator 12.
With reference to (b), the data pulse generator shown in this figure includes data electrodes D1, D2,.
m output terminals OUT1, OUT2,.
ＯＵＴ, OUTm. Two switches, a switch SWP inserted between the voltage input terminal 13 and a switch SWG inserted between the ground terminal 14, are connected to each output terminal. The voltage of each output terminal is switched to the voltage VD of the voltage input terminal 13 or the ground potential by opening and closing the two switches SWP and SWG complementarily. The video signal processing unit 11 controls which output terminal switch of the data pulse generation unit 12 is opened / closed in synchronization with each scan pulse by a signal SG1 generated based on the captured video signal. As a result, a data pulse having an amplitude VD is selectively applied to only the cell desired to be displayed among the m cells on one scanning electrode in synchronization with the scanning pulse.

During the sustain period TC, the interval between the scan electrode S1 and the common electrode C1 and the interval between the scan electrode S2 and the common electrode C2 are set to {
A sustain pulse vc is alternately applied for a predetermined time between a pair of the scan electrode and the common electrode, such as the scan electrode Sn and the common electrode Cn, to generate a predetermined address-generated cell during the scan period. Discharge and emit light only for the time. The address discharge in the previous scanning period TS is a discharge for selecting a display cell, whereas the sustain discharge in the sustain period TC is a discharge for causing the selected cell to emit light so that the selected cell can be visually recognized. In this case, the presence or absence of the sustain discharge is determined by the presence or absence of the address discharge in the previous scanning period. If the address discharge is insufficient and the wall charge is insufficient, the normal sustain discharge is not performed, and the flicker, lack of luminance, or a decrease in contrast may occur. Occurs. That is, the quality of the display screen deteriorates. Therefore, in many AC discharge type PDPs, a priming discharge period TP is provided before the scanning period TS so that the address discharge is reliably performed. Particularly, in a PDP having a large display capacity due to a large number of scanning electrodes and a high definition or a high gradation, it is important to reliably generate an address discharge in a short time in order to secure good display quality. Therefore, priming discharge is used. In order to reliably perform the priming discharge to all cells, the priming pulse vp is given a sufficient amplitude and pulse width.

In the erase period TE, the state of all cells in the panel is made uniform regardless of whether the cells are displayed or not. That is, an erase pulse ve, which is a wide low-voltage pulse or a narrow voltage pulse of the same width as the sustain pulse, is applied to all the scan electrodes S1,..., Sn. As a result, a discharge that neutralizes wall charges generated during the sustain period TC is generated by each of the scan electrodes S1,..., Sn and the common electrode C1,
維持 and Cn to stop the above-mentioned sustain discharge.

The above-described priming period TP and scanning period T
In one cycle of S, sustain period TC and erase period TE, an image for one field is displayed. By the way, since gradation cannot be displayed on an image only by the above-described line-sequential driving method, gradation control by a subfield method is usually combined in order to perform gradation display. That is, as shown in FIG.
The field T0 is divided into a plurality (four in this example) of subfields SF1, SF2,..., SF4.
The same priming period, scanning period, sustaining period, and erasing period as shown in FIG. 7 are provided for each subfield, and the length of each sustaining period is 1,1 / 2,1 between subfields. / 4, 1/8. In this way, the length of the sustain period in each subfield, that is, the light emission time, is weighted by 2 ^p (same as above, p = 4) to display 2 ^p gray scales (same as 2 ⁴ = 16 gray scales). It can be carried out. In such a gradation display by the subfield method, as shown in FIG.
Within a time period of 0, the priming period TP1, the scanning period TS1, the sustaining period TC1, and the erasing period TE1 of the first subfield SF1, the priming period TP2 of the second subfield SF2, the scanning period TS2, the sustaining period TC2, and the erasing period TE2.順次 are sequentially performed, and each of the sustain periods TS1, T
The time of S2,..., TS4 gradually decreases as the subfield advances.

The above-described gradation control by the subfield method is an example of a driving method in which a priming period is provided for each subfield. However, the present invention is not limited to this, and the priming period is applied once to a plurality of subfields. Is also available.

[0014]

As described above, in this type of AC discharge type PDP, in order to perform high-quality image display with high brightness and contrast without flicker, it is necessary to ensure that address discharge occurs during the scanning period. It is important to generate. Therefore, the scanning pulse and the data pulse include:
It is necessary to provide sufficient amplitude and pulse width. That is,
In general, the occurrence of a discharge in a gas space includes a stochastic factor, and is not limited to the write discharge, and the time from when a voltage is applied between discharge electrodes to when a discharge actually occurs (hereinafter, referred to as “discharge”).
The discharge delay time or simply referred to as the delay time) has a statistical variation. The magnitude of the variation in the delay time depends on the amplitude of the voltage applied between the discharge electrodes and the state of the discharge space. Therefore, regarding the AC discharge type PDP, when the address discharge is performed with a data pulse having a constant amplitude VD, if the width of the data pulse is narrow, the probability that the delay time of the address discharge exceeds the width of the data pulse is large. Therefore, there is a possibility that the address discharge does not occur. In order to prevent such an ignition failure of the address discharge due to the shortage of the data pulse width, the width of the data pulse is made sufficiently large with respect to the variation of the delay time of the address discharge, or the voltage between the electrodes is increased to increase the discharge delay time. By reducing the variation, it is ensured that the address discharge occurs.

A priming period is provided before the scanning period to generate a priming discharge prior to the address discharge, and electrons and ions are supplied into the cell to activate the cell (priming effect). Can be generated. However, even when the priming effect is used, if the amplitude VD and the pulse width of the data pulse are constant, the discharge tends to be less likely to occur in the later address discharge in time. That is, in the timing chart shown in FIG. 7, the address discharge is less likely to occur in the cell on the second scan electrode S2 than in the cell on the first scan electrode S1, and further, the third scan electrode As the discharge is more difficult in the cell on S3, it is less likely to occur in the later scan electrode. This is because the longer the elapsed time from the end of the priming discharge, the more the priming effect in the cell is attenuated, and the greater the variation in the delay time from the application of the data pulse to the start of the address discharge. Therefore, when the address discharge is performed with a data pulse having a constant amplitude VD and a constant pulse width (conventional example 1), even when the priming period is provided, the discharge delay time is longer in the address discharge after the scanning period. It becomes larger than the width of the data pulse, and there is a possibility that the address discharge does not occur during the time when the data pulse is applied. Therefore, the width of the data pulse is
The width Wdn must be large enough to reliably generate the address discharge even in the cell where the address discharge is performed by the last data pulse vdn in the scanning period.

From the foregoing, it can be said that whether the priming discharge is used or not, it is effective to increase the width of the data pulse in order to increase the reliability of the address discharge during the scanning period. However, if the widths of all the data pulses are uniformly increased in the driving method of the first conventional example, the time that must be divided into the scanning period in one field of a fixed time becomes longer. Possible time is reduced. As a result, the brightness decreases. Alternatively, in a panel that performs gradation display by the subfield method, the total time of the sustain period required for the gradation display (the sustain period TS1 of the first subfield + the sustain period TS2 of the second subfield + ‥‥ + the fourth subfield) The field maintenance period TS4) cannot be secured, and high gradation display becomes impossible. This is particularly remarkable in the case of a high-definition panel having a large number of scanning electrodes and a long scanning period. In other words, the width of the data pulse is set to be equal to the pulse width W required for the last address discharge in the scanning period throughout the entire scanning period.
In the driving method of the first conventional example in which data discharge is performed with a data pulse having a constant amplitude dn and a constant amplitude VD, a high-quality image with no flicker, high brightness and good contrast, and high definition are required. It can be said that it is difficult to achieve both high gradation.

One method (conventional example 2) for solving the above-mentioned problem is disclosed in Japanese Patent No. 2737697 by the same assignee of the present invention. In the driving method of Conventional Example 2, as shown in the timing chart of FIG.
With respect to d1, vd2,..., and vdn, the amplitude is set to the same constant amplitude VD as in the conventional example 1, and the pulse width is changed according to the elapsed time from the start of the scanning period.
The length of the entire scanning period is shorter than that of the first conventional example. That is, immediately after the start of the scanning period, the priming effect is still large and the variation in the delay time of the discharge is small, whereas in the latter half of the scanning period, the priming effect is weakened and the variation in the delay time becomes large. Therefore, the pulse width of the data pulse vd1 or the like at the beginning of the scanning period may be smaller than that of the pulse vdn or the like at the end of the scanning period. In other words, as in the first conventional example, the width of all data pulses is uniformly increased to be equal to the pulse width Wdn required for the address discharge at the end of the scanning period. It will be spread to. Therefore, if the pulse width of the first data pulse vd1 in the scanning period is narrowed to the required minimum width wd1, and the width of the subsequent data pulses is gradually increased gradually from wd1, the entire scanning period becomes the conventional example. 1 can be shortened. The invention of Conventional Example 2 reliably generates an address discharge in a shorter scanning period than the driving method of Conventional Example 1 in which an address discharge is performed with a data pulse having a constant amplitude and a constant width based on the above-described operation principle. As a result, high image quality, high definition, and high gradation are compatible.

However, even in the case of the invention of the conventional example 2, if the number of scanning electrodes is increased more than ever and a higher definition panel is to be obtained, the brightness, contrast or higher gradation is sacrificed. It must be. That is, if the number of scanning electrodes increases, inevitably,
Since the time from the beginning to the end of the scanning period, that is, the time from the end of the priming discharge to the application of the last data pulse vdn becomes longer, the attenuation of the priming effect becomes larger and the variation in the delay time of the address discharge becomes longer. growing. Therefore, the width Wdn of the data pulse vdn at the end of the scanning period must be widened by the variation in the delay time of the address discharge. After all,
Regardless of the method of the prior art 1 in which the address discharge is performed with a data pulse having a constant width or the method of the conventional example 2 in which the width of the data pulse is changed according to the elapsed time from the start of the scanning period, the number of scan electrodes is increased. In order to achieve higher definition, the increase in the delay time of the address discharge due to the increase in the number of scanning electrodes must be absorbed by increasing the width of the data pulse. However, it cannot meet the strong demand for high quality.

Therefore, the present invention is a method for driving an AC discharge type plasma display panel in which pulses are applied to scanning electrodes in a line-sequential manner. There is no need to lengthen the scanning period for writing discharge, and it is possible to perform a high gradation display, and furthermore, a driving method that can perform high-quality image display without flickering, lack of luminance or lowering of contrast without fail of writing discharge. It is intended to provide.

The present invention also provides the above-described high definition, high gradation,
It is an object of the present invention to provide an AC discharge type PDP capable of realizing a driving method capable of displaying high quality images.

[0021]

A plurality of scan electrodes of the present invention, a plurality of data electrodes orthogonal to the plurality of scan electrodes, and discharge cells arranged in rows and columns at intersections between the scan electrodes and the data electrodes. The data of the discharge cells to be displayed among the discharge cells on the scan electrode to which the scan pulse is applied while applying the scan pulse to the scan electrode line-sequentially for the AC discharge type plasma display panel having Selectively applying a data pulse synchronized with the scanning pulse to the electrode,
A method for driving a plasma display panel, comprising: a scanning period in which an address discharge is generated in a discharge cell to be displayed; and a sustain period in which a sustain cell is caused to perform a sustain discharge during the scanning period. The amplitude of the data pulse during the period is changed according to the elapsed time from the start of the scanning period.

In the method of driving a plasma display according to the present invention, the longer the elapsed time from the start of the scanning period, the larger the amplitude of the data pulse, and the greater the number of scanning electrodes to achieve high-definition display. The variance of the delay time is kept to be the same over the entire scanning period. Therefore, even when high definition display is performed, the width of the data pulse during the scanning period may be the same as in the related art, and does not need to be widened.

[0023]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a case in which an AC discharge type PDP according to the first embodiment of the present invention is driven.
FIG. 3 is a diagram illustrating a timing chart in a scanning period.
Referring to FIG. 1, in the driving method according to the present embodiment, each data pulse vd1, vd2,.
The amplitude of n is changed according to the elapsed time from the start of the scanning period. That is, the amplitude of the first data pulse in the scanning period is VD1, and the amplitude of the second data pulse is VD1.
The amplitude of the data pulse is made larger toward the later stage of the scanning period, for example, VD2 which is larger, Δ, and the amplitude of the last data pulse is the largest VDn.

In that case, the first data pulse v in the scanning period
The amplitude VD1 of d1 is the same as the constant amplitude VD of the data pulse in the first or second conventional example. By doing so, the pulse width of the first data pulse vd1 in the present embodiment can be reduced to at least the same width as the pulse width Wd1 of the first data pulse in Conventional Example 2. Thereafter, subsequent data pulses vd2, vd
The pulse widths of 3,..., And vdn are the same as the width Wd1 of the first data pulse vd1. As described above, by reducing the width of all data pulses to the narrowest data pulse width Wd1 of the second conventional example, the length of the scanning period is made shorter than that of the second conventional example. As a result, if the number of scanning electrodes is the same, the time that can be allocated to the sustain period in one field of a fixed time can be increased. A display without a mark is possible.

In the present embodiment, in the latter half of the scanning period, the width of the data pulse is narrower than the width of the data pulse at the same time in the first or second conventional example. But,
Since the amplitude at that time is increased, there is no problem in generating the address discharge. As described above, the magnitude of the variation in the delay time in the gas discharge depends on the voltage between the electrodes, and the higher the voltage, the smaller the variation. In the present embodiment, by utilizing this phenomenon, the amplitude of the data pulse in the latter half of the scanning period is made larger than in the conventional example 1 or 2 and the variation in the discharge delay time is reduced. Even if the width of the pulse is made narrower than in the related art, the address discharge can be reliably generated.

In the present embodiment, the variation of the delay time in the address discharge itself is suppressed by changing the amplitude of the data pulse which has been constant until now. Even when the number of scan electrodes is increased to perform high-definition display, the amplitude of the data pulse is sequentially increased as the number of scan electrodes increases, so that the variation in the delay time in the address discharge does not increase. To Even if the number of scanning electrodes increases, the magnitude of the variation in the discharge delay time does not change. Therefore, it is not necessary to increase the width of the data pulse even when performing the address discharge on the display cells on the increased scanning electrodes. The following is a comparison of the increment ΔTS of the scanning period between the present embodiment and Conventional Example 2 in the case where the number of scan electrodes, which has been n, is increased by q to n + q. In the case of the present embodiment ΔTS = q · Wd1 In the case of Conventional Example 2 ΔTS = q · Wdn + q · ΔW1 + (q−1) · ΔW2
+ ‥‥ + ΔWq where Wd1 is the pulse width of the first data pulse vd1 in the scanning period in Conventional Example 2, Wdn is the pulse width of the nth data pulse vdn in Conventional Example 2, and Wd1 <W
dn. ΔW1, ‥‥, and ΔWq are respectively
This is the difference in pulse width between a given data pulse corresponding to the increased q scan electrodes and the next data pulse.

From the above two equations, when the number of scanning electrodes is increased by q lines, the length of the scanning period TS simply increases in proportion to the increased number q in the present embodiment. On the other hand, in the conventional example 2, the width of each data pulse must be increased in accordance with the increase in the number of scan electrodes, as represented by the second term on the right side. Minutes will accumulate cumulatively. The difference between the increase in the scan period in the present embodiment and the increase in the scan period in Conventional Example 2 increases as the number of scan electrodes increases.

As described above, in the present embodiment, the length of the scanning period can be shorter than that of the related art if the number of scanning electrodes is the same as that of the related art. Further, even when the number of scanning electrodes is increased to achieve higher definition, it is not necessary to increase the length of the scanning period as compared with the related art. The advantage of the present embodiment when the number of scanning electrodes is increased is more remarkable as the number of scanning electrodes increases.

Next, a second embodiment of the present invention will be described. FIG. 2 is a diagram showing a timing chart in a scanning period when driving the AC discharge type PDP according to the second embodiment of the present invention. Referring to FIG. 2, in the driving method of the present embodiment, amplitude VD1 of data pulse vd1 at the beginning of a scanning period is made smaller than constant amplitude VD of the data pulse in Conventional Example 1 or Conventional Example 2. Then, the amplitude increases as the elapsed time from the start of the scanning period increases, and the data pulse vd at the end of the scanning period
The amplitude VDn of n is the same as the amplitude VD of the data pulse in the first or second conventional example. The pulse width of each data pulse is uniformly set to the pulse width Wdn of the data pulse in Conventional Example 1 (this pulse width Wdn is the same as the pulse width of the last data pulse vdn in the scanning period in Conventional Example 2). is there). in this way,
By making the amplitude of all data pulses smaller than the amplitude VD of the data pulse in the first or second conventional example and making the pulse width the same as that in the first conventional example, the power consumption during the scanning period is smaller than that in the first conventional example. Can also be reduced.

In this embodiment, at the beginning of the scanning period, the amplitude of the data pulse is set to the value of the conventional example 1 or the conventional example 2.
Is smaller than the amplitude of the data pulse in the same period, the variation in the delay time of the address discharge at this time becomes larger than that of the conventional example 1 or the conventional example 2. However, as described above, the priming effect is still large at the beginning of the scanning period, and setting the data pulse width at this time to be the same as the width Wdn of the data pulse at the end of the scanning period requires the variation in the delay time of the address discharge. Would have an unreasonably large margin. Therefore, even if the amplitude of the data pulse at the beginning of the scanning period is made smaller than before, the variation in the delay time in the address discharge becomes larger than before, there is no problem in the occurrence of the address discharge.

When the number of scan electrodes is increased in the present embodiment, the n-th scan electrode is increased as in the first embodiment.
The amplitude of the + 1st and subsequent data pulses is sequentially increased from VD in accordance with the number of scan electrodes increasing. Thus, the address discharge can be surely performed also on the cells on the increased scan electrodes without increasing the width of the data pulse. At this time, as in the first embodiment, the increase in the length of the scanning period TS is simply proportional to the increase in the number of scan electrodes, and unlike the conventional example 1 or the conventional example 2, In addition to the increase in the number of scan electrodes, there is no extra increase due to the need to increase the width of the data pulse in accordance with the increase in scan electrodes.

Next, in the first and second embodiments, the data pulses vd1, vd2,
‥‥ and vdn are generated as follows. FIG.
FIG. 3A is a block diagram illustrating a configuration of a data pulse generation portion according to the embodiment. Referring to FIG.
The data pulse in the embodiment is transmitted to the video signal processing unit 1
1, a data pulse generator 12, and a data voltage generator 1.
5 and the switch control unit 16. The embodiment is different from the conventional PDP panel in that a data voltage generation unit 15 and a switch control unit 16 are provided. The video signal processing unit 11 and the data pulse generation unit 12
(A) and (b) have the same structure as the conventional video signal processing unit and data pulse generation unit. The signal SG1 generated based on the video signal enables the same operation as the conventional one.
A data pulse synchronized with a scan pulse is selectively applied only to a cell to be displayed among m cells on one scan electrode. The amplitude of the data pulse at that time is determined by the voltage VDx applied to the voltage input terminal 13 of the data pulse generator 12. In the embodiment, the voltage VDx of the voltage input terminal 13 is
5 and the switch control unit 16 to change for each scanning electrode.

FIG. 3B is a circuit diagram showing an example of the data voltage generating section 13. Referring to FIG. 3B, data voltage generation unit 13 includes a DC power supply PS1 that outputs voltage VD1,
(N-
1) It is composed of DC power supplies PS2, PS3,..., PSn. Each power supply has VD2 <VD3 ‥‥ <
A voltage that becomes VDn is output. The output terminal of each power supply is connected to a common output terminal 17 via switches SW1,..., SWn connected to each power supply. The output voltage VDx of the common output terminal 17 is It is provided to a voltage input terminal 13. In this data voltage generation unit 15, n switches SW1,.
, The data voltage V applied to the data pulse generator 11 depends on which one of the switches is turned on.
The voltage value of Dx is determined.

When only the switch SW1 is turned on, the voltage VD1 is output. When only the switch SW2 is turned on, the voltage VD2 is superimposed on the voltage VD1 and the voltage VD1 is superimposed.
A voltage of + VD2 is output. Similarly, when only the switch SWn is turned on, the voltage VD1 + VD
n is output. Thus, the switches SW1,.
By sequentially switching SWn to the ON state, the voltage of the data voltage VDx applied to the data pulse generator 11 is sequentially increased.

Switch SW in data voltage generator 15
Opening / closing of 1,..., SWn is controlled by a signal SG2 from the switch control unit 16. Switch control unit 16
Are switches SW1,..., SWn of the data voltage generator 15 based on a signal SG2 generated based on a video signal.
Are sequentially switched in synchronization with the scanning pulse to be turned on. As a result, the voltage of the voltage input terminal 13 of the data pulse generating unit is sequentially switched to a higher voltage in synchronization with the scanning pulse, and the amplitude of the data pulse gradually increases according to the elapsed time from the start of the scanning period.

Here, the data voltage generating section 15
4B is not limited to the structure shown in FIG. 4B in which the voltage of another DC power supply is superimposed on the voltage VD1 of one DC power supply.
As shown in (a), switches SW1 and n are connected to n DC power supplies PS1, PS2,.
, SWn may be connected in parallel between the output terminal 17 and the ground terminal 14, and one of the n switches may be selected and turned on. Alternatively, as shown in FIG. 4B, n DC power supplies VD
, VD2,..., And VD are connected in series with reference to the ground potential, and each series connection node is connected to a switch S.
Connected to the output terminal 17 via W1,.
A structure in which one of the switches is selected and turned on may be used.

Next, a third embodiment of the present invention will be described. FIG. 5 shows a timing chart of the scanning period in this embodiment. Referring to FIG. 5, in the present embodiment, the scanning period is divided into three sub-periods: a first period, a second period, and a third period. Then, the amplitude of the data pulse is changed in sub-period units such that the data pulse in a sub-period having a longer elapsed time from the start of the scanning period has a larger amplitude. Within each sub-period, the amplitude of the data pulse is constant. The width of the data pulse is constant throughout the entire scanning period. The constant pulse width is set to a width Wdj that can surely cause an address discharge at the time of the last data pulse xdj of the first period. In this case, the width Wdj of the data pulse must be wider than the width Wd1 of the data pulse in the first embodiment, so that the effect of shortening the scanning period is smaller than that in the first embodiment. However, since the types of the amplitude of the data pulse are small, the number of DC power supplies and switches constituting the data voltage generating unit 15 can be reduced accordingly, and the configuration of the switch control unit 16 is simplified. Thereby, cost can be reduced. Needless to say, the number of divisions of the scanning period may be two instead of three, or four or more. Also, the number of data pulses included in each sub-period need not necessarily be the same.

The first, second, and third embodiments described above are not premised on the gradation control by the subfield method, but adopt the gradation control by the subfield method. Even when applied to a PDP panel, effects similar to those of the embodiment can be obtained. Further, although an example has been described in which the present invention is applied to a PDP panel using priming discharge, the present invention does not necessarily require the use of priming discharge. The present invention can be applied to a PDP that utilizes priming discharge and performs gradation control by a subfield method. In that case, the priming period may be provided for every subfield, or the priming discharge may be performed once for a plurality of subfields.

[0039]

As described above, according to the present invention, a scan pulse is applied line-sequentially to a scan electrode, and at the same time, a data pulse synchronized with the scan pulse is selectively applied to a cell to emit light. Discharge type PDP operated by
On the other hand, means for changing the amplitude of the data pulse in accordance with the elapsed time from the start of the scanning period is provided, and the longer the elapsed time of the data pulse is, the larger the amplitude is. So that it stays the same size.

According to the present invention, while ensuring a reliable address discharge, the time required for generating the address discharge in one field can be shortened, and the time for performing the sustain discharge can be increased accordingly. It is possible to display a high-quality image with high definition and without flicker, brightness, and contrast.

If the present invention is applied to a PDP that performs gradation display by the subfield method, it is possible to display an image with high definition and high gradation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a timing chart of a scanning period according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a timing chart of a scanning period according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a circuit that generates a data pulse according to the first embodiment and the second embodiment of the present invention, and a circuit diagram of an example of a data voltage generation unit.

FIG. 4 is a circuit diagram of another example of the data voltage generator and a circuit diagram of a third example.

FIG. 5 is a diagram illustrating a timing chart of a scanning period according to a third embodiment of the present invention.

FIG. 6 is a diagram schematically illustrating an example of a planar structure of an AC discharge type PDP panel, and a diagram illustrating a cross-sectional structure of an example of a discharge cell.

FIG. 7 is a diagram showing a timing chart when an AC discharge type PDP panel is driven by the method of Conventional Example 1.

FIG. 8 is a block diagram of a circuit for generating a data pulse in a conventional AC discharge type PDP panel, and a circuit diagram of an example of a data pulse generator.

FIG. 9 is a diagram showing a sequence when performing gradation control by a subfield method.

FIG. 10 is a diagram showing a timing chart of a scanning period when an AC discharge type PDP panel is driven by the method of Conventional Example 2.

[Explanation of symbols]

 Reference Signs List 1A, 1B substrate 2 dielectric layer 3 protective layer 4A1, 4A2, 4B1, 4B2 partition wall 5 dielectric layer 6 phosphor 7 8 discharge gas space 9 10 cell 11 video signal processing unit 12 data pulse generation unit 13 voltage input terminal 14 ground Terminal 15 Data voltage generator 16 Switch controller 17 Output terminal S Scan electrode C Common electrode D Data electrode

Claims (8)

[Claims] 1. An AC discharge type plasma comprising a plurality of scan electrodes, a plurality of data electrodes orthogonal thereto, and discharge cells arranged in rows and columns at intersections of the scan electrodes and the data electrodes. While applying a scan pulse line-sequentially to the scan electrodes on the display panel, the scan pulse is applied to the data electrodes of the discharge cells to be displayed among the discharge cells arranged along the scan electrodes to which the scan pulse is applied. A scan period in which a synchronous data pulse is selectively applied to generate an address discharge in the discharge cell to be displayed, and a sustain period in which a sustain discharge is performed in the discharge cell in which the address discharge is generated during the scan period. A method of driving a plasma display panel, comprising: changing an amplitude of a data pulse during the scanning period according to an elapsed time from a start of the scanning period. The driving method of plasma display panel. 2. The method of driving a plasma display panel according to claim 1, wherein the amplitude of the data pulse in the scanning period is increased in units of data pulse as the elapsed time from the start of the scanning period is longer. . 3. The scanning period is divided into a plurality of sub-periods in which the amplitude of the data pulse is constant within each period, and the amplitude of the data pulse in the scanning period is changed in units of the sub-period from the start of the scanning period. 2. The method according to claim 1, wherein the longer the elapsed time, the larger the time. 4. The driving method for a plasma display panel according to claim 2, wherein a priming period for generating a priming discharge for all discharge cells is provided prior to the scanning period. 5. One field for displaying one screen is composed of a plurality of subfields each having a scanning period and a sustaining period, and the length of the sustaining period of each subfield is made different to correspond to the number of subfields. 4. The method according to claim 2, wherein a gradation display is performed. 6. The priming period is provided once for each subfield.
3. The method for driving a plasma display panel according to item 1. 7. The method according to claim 4, wherein the priming period is provided once for each of a plurality of subfields. 8. A plurality of scan electrodes, a plurality of data electrodes orthogonal to the scan electrodes, and an AC discharge type discharge arranged in rows and columns at intersections of the scan electrodes and the data electrodes. A data pulse comprising: a cell; a voltage input terminal; and a plurality of output terminals corresponding to the data electrodes on a one-to-one basis, and outputting a data pulse having an amplitude of a voltage applied to the voltage input terminal to each data electrode. Generating means, based on a given video signal, the data pulse generating means, in synchronization with a scan pulse applied line-sequentially to the scan electrode, along a scan electrode to which the scan pulse is applied. First control means for selectively outputting data pulses to the data electrodes of the discharge cells to be displayed among the discharge cells arranged in a line, and inputting a voltage to a voltage input terminal of the data pulse generation means. A data voltage generating means that outputs a voltage to be output, and an output voltage can be switched, and, based on the video signal, scans the data voltage generating means in synchronization with a scan pulse applied line-sequentially to the scan electrodes. A plasma display panel comprising: a second control unit configured to control to output a voltage that sequentially increases in pulse order.